Nerve growth factor inducer, 4-methyl catechol, potentiates central sensitization associated with acceleration of spinal glutamate release after mustard oil paw injection in rats.

1. In rats, injection of mustard oil (MO) into the paw caused a gradual increase in flinching of the injected paw and this algogenic behavior corresponded with an increase in the CSF-Glu level. 2. The nerve growth factor (NGF) inducer, 4-methyl catechol (4MC), enhanced the frequency of flinching and this effect was dose dependent. In addition, spinal CSF-Glu release was significantly above baseline 10 min after MO injection. In contrast, morphine (MOR) pretreatment completely blocked this behavioral and neurohumoral effect. 3. Anti-NGF paw injection attenuated the algogenic behavior and spinal Glu release otherwise observed after 4MC treatment. 4. The results demonstrated that MO-induced hyperalgesia is associated with increased CSF-Glu release and that this effect is potentiated by a NGF inducer. These data also suggest a possible involvement of NGF in the development of central sensitization after acute peripheral nociceptive stimulation.